Browsing by Autor "Martin Jansen"

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A camera trapping survey of mammals in the mixed landscape of&nbsp;Bolivia&rsquo;s Chiquitano region with a special focus on the Jaguar
(Pensoft Publishers, 2020) Martin Jansen; Marc Engler; Luka Moritz Blumer; Damián I. Rumiz; José Luis Aramayo; Oliver Krone
At a site in the Bolivian Chiquitano region composed by a mosaic of pastureland and primary Chiquitano Dry Forest&nbsp;(CDF) we conducted a camera-trapping study to (1) survey the mammals, and (2) compare individual Jaguar numbers&nbsp;with other Chiquitano sites. Therefore, we installed 13 camera stations (450 ha polygon) over a period of six months.&nbsp;On 1,762 camera-days and in 1,654 independent capture events, we recorded 24 mammalian species that represent the&nbsp;native fauna of large and medium-sized mammals including apex-predators (Puma, Jaguar), meso-carnivores (Ocelot,&nbsp;Jaguarundi, Margay), and large herbivores (Tapir, Collared and White lipped Peccary). We identified six adult Jaguars&nbsp;and found indications of successful reproductive activity. Captures of Jaguars were higher in CDF than in altered habitats.&nbsp;In summary, we believe that (1) the mammal species richness, (2) the high capture numbers of indicator species,&nbsp;and (3) the high capture numbers of Jaguar indicate that our study area has a good conservation status. Future efforts&nbsp;should be undertaken to keep this, and monitoring programs in this region are necessary to further evaluate the potential&nbsp;importance of the Chiquitano region as a possible key region for mammals, especially Jaguars, in South America.
Accuracy, limitations and cost efficiency of eDNA‐based community survey in tropical frogs
(Wiley, 2018) Miklós Bálint; Carsten Nowak; Orsolya Márton; Steffen U. Pauls; Claudia Wittwer; José Luis Aramayo; Arne Schulze; Thierry Chambert; Berardino Cocchiararo; Martin Jansen
Rapid environmental change in highly biodiverse tropical regions demands efficient biomonitoring programmes. While existing metrics of species diversity and community composition rely on encounter-based survey data, eDNA recently emerged as alternative approach. Costs and ecological value of eDNA-based methods have rarely been evaluated in tropical regions, where high species richness is accompanied by high functional diversity (e.g., the use of different microhabitats by different species and life stages). We first tested whether estimation of tropical frogs' community structure derived from eDNA data is compatible with expert field assessments. Next, we evaluated whether eDNA is a financially viable solution for biodiversity monitoring in tropical regions. We applied eDNA metabarcoding to investigate frog species occurrence in five ponds in the Chiquitano dry forest region in Bolivia and compared our data with a simultaneous visual and audio encounter survey (VAES). We found that taxon lists and community structure generated with eDNA and VAES correspond closely, and most deviations are attributable to different species' life histories. Cost efficiency of eDNA surveys was mostly influenced by the richness of local fauna and the number of surveyed sites: VAES may be less costly in low-diversity regions, but eDNA quickly becomes more cost-efficient in high-diversity regions with many sites sampled. The results highlight that eDNA is suitable for large-scale biodiversity surveys in high-diversity areas if life history is considered, and certain precautions in sampling, genetic analyses and data interpretation are taken. We anticipate that spatially extensive, standardized eDNA biodiversity surveys will quickly emerge in the future.
Accuracy, limitations and cost-efficiency of eDNA-based community survey in tropical frogs
(2017) Miklós Bálint; Carsten Nowak; Orsolya Márton; Steffen U. Pauls; Claudia Wittwer; B. Jose Luis Aramayo; Arne Schulze; Thierry Chambert; Berardino Cocchiararo; Martin Jansen
Abstract Rapid environmental change in highly biodiverse tropical regions demands efficient biomonitoring programs. While existing metrics of species diversity and community composition rely on encounter-based survey data, eDNA recently emerged as alternative approach. Costs and ecological value of eDNA-based methods have rarely been evaluated in tropical regions, where high species richness is accompanied by high functional diversity (e.g. the use of different microhabitats by different species and life-stages). We first tested whether estimation of tropical frogs’ community structure derived from eDNA data is compatible with expert field assessments. Next we evaluated whether eDNA is a financially viable solution for biodiversity monitoring in tropical regions. We applied eDNA metabarcoding to investigate frog species occurrence in five ponds in the Chiquitano dry forest region in Bolivia and compared our data with a simultaneous visual and audio encounter survey (VAES). We found that taxon lists and community structure generated with eDNA and VAES correspond closely, and most deviations are attributable to different species’ life histories. Cost efficiency of eDNA surveys was mostly influenced by the richness of local fauna and the number of surveyed sites: VAES may be less costly in low-diversity regions, but eDNA quickly becomes more cost-efficient in high-diversity regions with many sites sampled. The results highlight that eDNA is suitable for large-scale biodiversity surveys in high-diversity areas if life history is considered, and certain precautions in sampling, genetic analyses and data interpretation are taken. We anticipate that spatially extensive, standardized eDNA biodiversity surveys will quickly emerge in the future.
Description of a new species of Xenopholis (Serpentes: Colubridae) from the Cerrado of Bolivia, with comments on Xenopholis scalaris in Bolivia
(Q15088586, 2009) Martin Jansen; Lucindo Gonzales Álvarez; Günther Köhler
We describe a new species of Xenopholis from the Chiquitano Region in the eastern lowlands of Bolivia. The new species can be identified as member of the genus Xenopholis by its vertebral morphology. The new species differs from the other two species of Xenopholis in its unique, uniform dorsal color pattern. It further differs from X. scalaris by having two prefrontals and a narrow septum within each neural spine and perpendicular to its long axis. For X. scalaris we present new records from Bolivia, including the highest altitudinal record for the species and genus (Serranía Beu in the Pilón Lajas Reserve, Department of La Paz, 1500 m).
Engaging Citizen Scientists in Biodiversity Monitoring: Insights from the WildLIVE! Project
(Ubiquity Press, 2024) Martin Jansen; Maya Beukes; Claus Weiland; Moritz Blumer; Markus Rudolfi; Julia Poerting; René Meißner; Merlin Weiß; Yannet Condori; Gabriel Aramayo Ledezma
The growing public interest in biodiversity monitoring has led to a significant increase in initiatives that unite citizen scientists, researchers, and machine learning technologies. In this context, we introduce WildLIVE!, a dynamic biomonitoring and citizen science project. In WildLIVE!, participants analyze a vast array of images from a long-term camera trapping project in Bolivia to investigate the impacts of shifting environmental factors on wildlife. From 2020 to 2023, more than 850 participants registered for WildLIVE!, contributing nearly 9,000 hours of voluntary work. We explore the motivators and sentiments of participant engagement and discuss the key strategies that have contributed to the project’s initial success. The findings from a questionnaire highlight that the primary motivational factors for our participants are understanding and knowledge, as well as engagement and commitment. However, expressions of positive and negative sentiments can be found regarding involvement. Participants appeared to be driven primarily by a desire for intellectual growth and emotional fulfillment. Factors crucial to the success of this digital citizen science project include media exposure, creating emotional connections through virtual and in-person communication with participants, and visibility on public citizen science portals. Moreover, the project’s labeled dataset serves as a valuable resource for machine learning, aiding the development of a new platform that is compliant with the FAIR principles. WildLIVE! not only contributes to outcomes in science, society, and nature conservation, but also demonstrates the potential of creating a collaborative bridge between the general public, scientific research, biodiversity conservation, and advanced technological applications.
Fires scorching Bolivia's Chiquitano forest
(American Association for the Advancement of Science, 2019) Alfredo Romero‐Muñoz; Martin Jansen; Angela M. Nuñez; Marisol Toledo; Roberto Vides Almonacid; Tobias Kuemmerle
Habitat destruction threatens jaguars in a mixed land use region of eastern Bolivia
(2022) René Meißner; Moritz Blumer; Merlin Weiß; Maya Beukes; Gabriel Aramayo-Ledezma; Yannet Condori; José Luis Aramayo-Bejarano; Martin Jansen
Large carnivores such as the jaguar (Panthera onca) are particularly susceptible to population decline and local extinction as a result of habitat loss. Here, we report on the long-term monitoring of a local jaguar population in a mixed land use area in the eastern lowlands of Bolivia from March 2017 to December 2019. We recorded 15 jaguar individuals and four reproduction events (five offspring from three females), suggesting that our study area harbors a resident breeding population. Seven iterations of spatially explicit capture-recapture models provided density estimates ranging from 1.32 to 3.57 jaguars per 100 km². Jaguar capture rates were highest in forested areas, with few to no jaguar captures occurring in pastures used for livestock. Massive deforestation after the survey period reduced the proportion of dense forest cover by 33%, shrinking the availability of suitable jaguar habitat and placing the resident jaguar population at risk. We use the jaguar as an indicator species to highlight the threat of habitat destruction in the Chiquitano region and to emphasize the importance of intact forest patches for jaguar conservation.
Habitat destruction threatens jaguars in a mixed land-use region of eastern Bolivia
(Cambridge University Press, 2023) René Meißner; Moritz Blumer; Merlin Weiß; Maya Beukes; Gabriel Aramayo Ledezma; Yannet Condori Callisaya; José Luis Aramayo Bejarano; Martin Jansen
Abstract Large carnivores such as the jaguar Panthera onca are particularly susceptible to population decline and local extinction as a result of habitat loss. Here we report on the long-term monitoring of a local jaguar population in a mixed land-use area in the eastern lowlands of Bolivia from March 2017 to December 2019. We recorded 15 jaguar individuals and four reproduction events (five offspring from three females), suggesting that our study area harbours a resident breeding population. Seven iterations of spatially explicit capture–recapture models provided density estimates of 1.32–3.57 jaguars per 100 km 2 . Jaguar capture rates were highest in forested areas, with few to no jaguar captures in pastures used for livestock. Massive deforestation after the survey period reduced the proportion of dense forest cover by 33%, shrinking the availability of suitable jaguar habitat and placing the resident jaguar population at risk. We use the jaguar as an indicator species to highlight the threat of habitat destruction in the Chiquitano region and we emphasize the importance of intact forest patches for jaguar conservation.
New Species of Hydrolaetare (Anura, Leptodactylidae) from Bolivia with Some Notes on Its Natural History
(The Society for the Study of Amphibians and Reptiles, 2007) Martin Jansen; Lucindo Gonzales Álvarez; Günther Köhler
We describe a new species of Hydrolaetare from the eastern lowlands of Bolivia. The new species differs from the other two congeners in (1) Finger II and III with lateral fringes only on the inner side; (2) relative length of first finger; (3) palmar tubercle distinctly larger than thenar tubercle; (4) toes semiwebbed; and (5) coloration. Moreover, the advertisement call of the new species differs from that of its congeners. Some information about its natural history is given.
Primer registro de Leopardus braccatus (Carnivora: Felidae) en el bosque seco chiquitano, Bolivia
(2024) Paola Nogales‐Ascarrunz; Gabriel Aramayo Ledezma; Enzo Aliaga - Rossel; José Luis Aramayo-Bejarano; Mauro Lucherini; Martin Jansen
El complejo del Leopardus colocolo, según una reciente actualización taxonómica, ha sido dividido en cinco especies. Una de estas es el Leopardus braccatus conocida como gato del pantanal, distribuido en Bolivia, Brasil y Paraguay. A pesar de su distribución, esta es una especie poco estudiada. Presentamos aquí un nuevo registro de esta especie, siendo el primero en el bosque seco chiquitano, un ecosistema amenazado que previamente no se consideraba su hábitat. Este hallazgo se llevó a cabo como parte de un programa de monitoreo de felinos con cámaras trampa, donde adicionalmente seis especies de félidos fueron detectadas en un área de 41km2, lo que indica una alta diversidad de felinos en esta ecorregión. Además, se identificaron amenazas directas para el gato del pantanal, como la actividad agrícola y ganadera, los perros domésticos y la cacería ilegal. La relevancia de este nuevo registro radica en su ubicación en el límite occidental-sur de la distribución conocida para Bolivia, así también como sus características morfológicas similares a la especie L. munoai. Esto subraya la necesidad de realizar investigaciones adicionales para comprender mejor su distribución y conservación. Estudios futuros podrían explorar también las similitudes morfológicas y de distribución entre L. braccatus y L. munoai.
Twenty-five species of frogs in a liter of water: eDNA survey for exploring tropical frog diversity
(2017) Miklós Bálint; Carsten Nowak; Orsolya Márton; Steffen U. Pauls; Claudia Wittwer; José Luis Aramayo; Arne Schulze; Thierry Chambert; Berardino Cocchiararo; Martin Jansen
Biodiversity is declining at unprecedented rates, with species extinctions being an important component of this process. Currently it is almost impossible to evaluate this loss since biodiversity data is lacking even for emblematic species. Recent advances in eDNA marker gene studies promise to deliver the necessary data, but these approaches have almost never been evaluated in the tropics. Here we evaluate whether 1) eDNA metabarcoding may reliably generate frog faunistic data in species-rich tropical areas, 2) the ecological signal in eDNA data is compatible with data from visual and audio encounter survey (VAES), and 3) eDNA data represent a financially viable solution to biodiversity data acquisition. We applied eDNA metabarcoding to investigate frog species occurrence in five ponds in the Chiquitano dry forest region in Bolivia and compared our data with a simultaneous VAES. We find that taxon lists generated with eDNA and VAES correspond closely, and most deviations are attributable to different species' life histories. The ecological signal in eDNA closely matches the signal from VAES. We find that the cost efficiency of eDNA surveys is mostly influenced by the richness of local fauna and the number of surveyed sites: VAES may be less costly in low-diversity regions, but eDNA quickly becomes more cost-efficient in high-diversity regions, particularly with many sites. The results underline that eDNA is suitable for large-scale biodiversity surveys in high-diversity areas if precautions in data generation and interpretation are taken and this projects spatially extensive standardized biodiversity surveys in the close future.
Understanding multiple pathways of the impacts of socio‐economic shocks on large carnivores
(Wiley, 2025) Ranjini Murali; Altynai Adabaeva; Sixto Angulo; Rosario Arispe; Matthias Baumann; Arash Ghoddousi; Amirhossein Khaleghi Hamidi; Martin Jansen; Leili Khalatbari; Igor Khorozyan
Abstract Large carnivores are ecologically, economically and socially important, but they are also among the most threatened species worldwide. These species face numerous threats, most importantly habitat transformation, prey depletion and hunting. All of these threats could be exacerbated by socio‐economic shocks—such as financial crises, wars, pandemics or political regime shifts—that can cause sudden and structural changes in social‐ecological systems. However, the different pathways through which such shocks impact large carnivores are unclear. Here, we used a social‐ecological systems approach to build a conceptual framework that investigates these pathways. We used expert workshops and case‐specific, narrative literature reviews to illustrate this framework for three cases: (1) impacts of economic sanctions on the Asiatic cheetah ( Acinonyx jubatus venaticus ) in Iran, (2) impacts of global commodity price shocks on the jaguar ( Panthera onca ) in Bolivia and (3) impacts of the collapse of the Soviet Union on the snow leopard ( P. uncia ) in Kyrgyzstan. We found that conservation and agricultural institutions were crucial for carnivore conservation, despite the different nature of the shocks and the different socio‐economic settings across cases. We identified linkages between carnivore conservation and the global economy at the levels of nations and communities, which increased the vulnerability of carnivores to shocks. Our cases highlighted the need to proactively create resilient institutions focused on local capacity building, enhancement of social stability and built on internal motivations for conservation, to secure the future of large carnivores in turbulent times. Read the free Plain Language Summary for this article on the Journal blog.